This invention relates in general to vehicle steering gears and in particular to an improved rack ball nut assembly for use in such vehicle steering gears and related components thereof.
One known power steering gear for turning steerable wheels of a vehicle includes a rack ball nut assembly for transmitting force between an axially movable rack member and a power source. For example, the power source may be an electric motor or hydraulic system. Upon actuation of the power source, the ball nut is driven to rotate relative to the rack member and the rotational force of the ball nut is transmitted to the rack member by balls that drive the rack member axially. The axial movement of the rack member by the balls effects turning movement of the steerable wheels. Turning movement of the steerable wheels is controlled by a driver rotating a steering wheel. Rotating the steering wheel activates the power source.
The rack ball nut assembly typically includes a means for returning the balls from a first end to a second end of the ball nut. Commonly, the means is a ball return tube secured by a clip screwed to the ball nut, which increases complexity of assembling the rack ball nut assembly. The ball return tube may be manufactured from tube portions that are welded together. However, welding the tube portions together may result in defects or other undesirable effects. For example, laser welding may distort geometry of the tube and ultrasonic welding may create flash during welding. Thus, it would be desirable to have a rack ball nut assembly that did not require screws or welding.